The present invention relates to the field of oil and gas drilling and in particular to apparatuses for the containment and control of the flow of hydrocarbons from oil and gas wells.
An inherent risk in oil and gas exploration is the unintended release of oil or gas into the environment. A common cause for these releases are sudden pressure variations during the drilling process (so called kicks), usually caused by influx of formation fluids into the well bore. If the formation fluids are allowed to reach the surface, well tools and other drilling material may be blown out of the wellbore. These blowouts may result in destruction of the drilling equipment and injury or death to rig personnel. The main tool to prevent spills from these pressure variations used today are blowout preventers which essentially represent sealing devices to seal off the wellbore until active measures can be taken to control the kick. However, even with blowout preventers in place, the risk of oil spills remains. Spills can still occur due to material failure of the blowout preventer resulting from excessive pressure or accidental disruption of conducting components such as riser pipes, as well as catastrophic destruction of drilling platforms. Once a spill has occurred, measures must be taken to contain it. In previously occurring oil spills those measures have included the permanent sealing of the wellbore with filling material, and capturing the spilling oil by temporary capping of the well.
It has been recognized that known blowout preventer systems are susceptible to leaks due to material failure under high pressure. Especially in deep sea oil drilling, blowout preventers are subjected to enormous stress from external hydrostatic pressure of seawater and formation fluid pressure of the wellbore. Blowout preventers commonly used today consist of many interconnected parts with gaskets meant to seal leakage of formation fluids through the sites of interconnection. An example for a typical blowout preventer used in oil exploration is U.S. Pat. No. 7,300,033. The high stress exerted on the interconnecting spaces and gaskets makes these elements sites for potential leaks. In addition, current blowout preventer systems lack the ability to detect the build up of gas at the wellbore and relay this information to drilling personnel. Further, it has been generally recognized that current systems for emergency containment and recovery of oil spills are inadequate. An example for such a system is the apparatus used during the oil spill from the Moncado oil well in the Gulf of Mexico in 2010. The apparatus used in the Moncado oil spill essentially represents a dome designed to enclose the ruptured oil pipe. At its top this dome can be connected to a riser pipe. After placement of the device over the ruptured pipe of the Moncado well, hydrates formed due to low temperature, and accumulated in the upper region of the dome, preventing oil flow from the device into the riser pipe. Since the hydrates are lighter than water they also caused the device to become buoyant and float upwards. The attempt to contain the Moncado well and recover the spilling oil using the containment structure eventually failed. Further, emergency containment systems currently in use do not have the ability to regulate oil flow in real time but can only operate on an on or off basis.
It would therefore be desirable and advantageous to provide an improved blow-out preventer and oil spill recovery management system to obviate prior shortcomings of other systems and to provide a system in which stress on the device from formation fluid pressure is minimized, which is able to detect gas build up during drilling operations at the wellbore, and which is better adapted to respond to emergency oil spills.